hi people!
4 Years ago I try to midify a Siel mono, an analog sinth made in italy in 1980
but in a wrong operation, I burn the main chip , a pretty rare and expensive “m110”. :-((
This is a 40 pin ic product by SGS in early 80, and it’s used in many
vintage sinth like Siel mono,cruise, or Jen SX1000.
http://www.milton.arachsys.com/nj71/pdf/m110.pdf
This chip scan the matrix of keyboard and a dco (clocked by 1 mhz I think) make the
square wave output for the note.
The m110 is very hard to find and much expensive, so i think about a project (pic based) to make a clone.
In the net I have found this board but the core is an Atmel ATMEGA8L (!!!)
http://www.milton.arachsys.com/nj71/index.php?menu=2&submenu=4&subsubmenu=1
(look “3.5 Keyboard” section!)
At this time i’m building a 1 rack unit MIDIbox SID Synthesizer (soon the pics …), and I ask me
if is possible a project mios based like a replacement module of the dead m110.
Any Idea?!?
Why do you not want to use the Atmel project? My guess is that you could do this with a PIC processor but that it is going to be a LOT of work.
Hello dott.benway,
You should check Neil Johnson’s page.
He built a M110 replacement with an Atmega8 controler.
http://www.njohnson.co.uk/ in the Jen SX1000 Restoration section.
The schematics are there and the firmare for the Atmega8 are also there.
Regards,
Pascal
I think 3 way to resume the dead m110 :
- I buy a new m110 chip.
I have found it on e-bay for 40 €.I’ts very expensive, cause I take the sinth from a friend 5 years ago for 10 € !!!
but this mean no midi, or build another midi interface pic based …
http://www.electronic-obsession.se/studio/mono/mono.html
http://www.electronic-obsession.se/studio/mono/mono_mtc64.JPG
http://www.electronic-obsession.se/studio/mono/mono_vco.JPG
- build the atmel board.
Mmm … long story. I need to build a specific programmer,install another sofware (…)
@ this time I’m building 2 core modules + the pic burner: another project Atmel based sound like “no-sense”!
- A core module based project.
This can be a great alternative:with a cv/gate out, I can control the synth via midi,but in this case
the keyboard of the synth not work!
but … if I add an input (like a din module ? ), I can connect the matrix of the keyboard and … GOAL!!! 
Maybe i’ts like kill a fly with a cannon ball,but I think this is a good start point about a midify-discussion.
… and many peole are “luky” m110 owner! 
a) Easy, expensive
b) Easy, cheap
c) Will take you many months of programming and lots of effort in prototyping and testing, and probably a sizable sum of $ on spare parts.
Take option B mate. I don’t think you realise just how hard option C is.
Sebo
6
Hi:
I have the same problem but with a 4 voice polyphonic Yamaha CS-50 (the
chip that sacan the keyboard matrix is broken, and is very hard to find and expensive).
I buyed a a PAiA MIDI to CV interface very cheap (second hand), but is V/Oct
and I need Hz/Oct so I’m in the process to do some mods to it.
But I can’t use the beatiful keyboard (that have aftertouch). So I’m planing
to add a PIC based circuit to scan the matrix and convert the signals to MIDI.
I found this project http://tomscarff.tripod.com/key2midi/key2midi.htm based
on a PIC16F877, is really simple.
Sebo
Hey Sebo,
PAIA makes an add on board that will turn the V/Oct to V/Hz.
9700vhz midi2cv8 Volts/Hertz Option
includes all components and circuit
board with mounting hardware … us$14.25 (5.00)
the above from thier website at:http://paia.com/midi2cv.htm
gb
I found this project http://tomscarff.tripod.com/key2midi/key2midi.htm based
on a PIC16F877, is really simple.
Did you check out QBAS’s MIOS-based keyboard scanning matrix?
Sebo
9
HI ppl:
Tanstaafl:
Thanks for the advice, but PAiA is not selling the CV/Hz converter anymore.
I contacted them and they give me the schematics and some info. I’m in
the process of making it, but the transistors that the circuit uses aren’t
avlaible in my country, so I’m triying some others.
stryd_one:
I didn’t know about it, I gonna do a search at the forum. Thank you.
Sebo
Hi Mr. Sebo!
what’s the name of the Chip broken?
I buy for 40 euro a M110 @ this page : http://www.vintagechip.altervista.org/
Maybe u can find your chip .
(…)
Do u need a black box like this?
_____
>– V/oct —| |
| VCO | ----> ////\ (square wave)
|_____|
Try this simple schematic:
http://www.uni-bonn.de/~uzs159/vco4069.html
(…)
A very very good analog keyboard interface project is this :
http://www.musicfromouterspace.com/analogsynth/AAA_VControllerIndex.html
http://www.musicfromouterspace.com/analogsynth/matrix_keyboard_may2004/matrix_keyboard_may2004.html
Maybe this can be a great T.O.S. substitute
(T.O.S. mean Top Octave Synthesizer or what?!? )
Soon the pictures of The “re-animation” of my Siel mono !!!

Sebo
11
Hi dott.benway:
Thanks for the links & info.
Sadly that site don’t have the chips. They are customs chips made by Yamaha
YM2600 & YM2700.
The big problem is that most people want them for the bigger CS-80 so when
someone have one ask a really high price, that sometime is most that my CS-50
costs 
I will check the sites for the keyboard interfaces.
Sebo